Composite Cable

ABSTRACT

Both deformation of a cross-sectional shape of the entire composite cable and deformation of a cross-sectional shape of an electric wire included in the composite cable are suppressed. The composite cable includes: a plurality of first electric wires; a shield electric wire in which a shield layer  33  is formed around a twist pair wire  32  obtained by intertwining a plurality of second electric wires; a sheath formed around an electric wire assembly obtained by intertwining the first electric wires and the shield electric wire; a first line filler filled between the twist pair wire and the shield layer; and a second line filler filled between the electric wire assembly and the sheath. While the first electric wires and the shield electric wire are intertwined in a first direction, the second electric wires are intertwined in a second direction that is opposite to the first direction.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese Patent ApplicationNo. 2018-129099 filed on Jul. 6, 2018, the content of which is herebyincorporated by reference into this application.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a composite cable including at leasttwo types of electric wires.

BACKGROUND OF THE INVENTION

A composite cable having an assembly of a plurality of power supplywires and a plurality of signal wires (referred to as “electric wireassembly” in some cases below) and a sheath layer formed around thiselectric wire assembly has been known. That is, a composite cable inwhich an assembly of a plurality of electric wires is covered with asheath layer has been known. The plurality of signal wires included inthe electric wire assembly are intertwined with one another, and ashield layer is formed around the plurality of signal wires that areintertwined (Japanese Patent Application Laid-Open Publication No.2006-351322: Patent Document 1).

SUMMARY OF THE INVENTION

Generally, in a composite cable described in the Patent Document 1 andother composite cables, a filler is formed between the electric wireassembly and the sheath layer in order to maintain a circularcross-sectional shape of such a composite cable.

However, in some cases, when the filler is formed between the electricwire assembly and the sheath layer, the shield layer formed around thesignal wires is compressed by a pressure applied by the filler, and thecross-sectional shape of the shield layer cannot be circular. When thecomposite cable is bent with the originally-circular cross-sectionalshape of the shield layer deforming into a shape other than the circularshape, there is a risk of breakage of the shield layer. Particularly,even a shield layer that has not been broken at the time of one bendingof the composite cable has high possibility of breakage when thecomposite cable is repeatedly bent with the cross-sectional shape of theshield layer deforming.

As described above, a related-art composite cable has such a problem ascausing the deformation of the cross-sectional shape of the shield layerformed around the signal wires due to the filler used for maintainingthe cross-sectional shape of the entire composite cable to be circular.

The present invention has been made in consideration of theabove-described problem, and an object of the present invention is tosuppress the deformation of the cross-sectional shape of the shieldlayer formed around the signal wires while the circular cross-sectionalshape of the composite cable is maintained.

A composite cable of the present invention includes: a plurality offirst electric wires; a shield electric wire in which a shield layer isformed around a stranded electric wire obtained by intertwining aplurality of second electric wires; a sheath formed around an assemblyobtained by intertwining the plurality of first electric wires and theshield electric wire; a first line filler filled between the strandedelectric wire and the shield layer; and a second line filler filledbetween the assembly and the sheath. While the plurality of firstelectric wires and the shield electric wire are intertwined in a firstdirection, the plurality of second electric wires included in the shieldelectric wire are intertwined in a second direction that is opposite tothe first direction.

In one aspect of the present invention, the second line filler isintertwined together with the first electric wires and the shieldelectric wire in the first direction, and the first line filler isintertwined together with the second electric wires in the seconddirection.

In another aspect of the present invention, a filling rate of the firstline filler is higher than a filling rate of the second line filler.

In still another aspect of the present invention, the first line fillerand the second line filler have the same cross-sectional area as eachother, and the number of the first line filler per a unitcross-sectional area is larger than the number of the second line fillerper a unit cross-sectional area.

In still another aspect of the present invention, the first electricwire and the second line filler are directly in contact with each other.

According to the present invention, the deformation of thecross-sectional shape of the shield layer formed around the plurality ofsignal wires can be suppressed while the cross-sectional shape of thecomposite cable is maintained.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 is a cross-sectional view showing one example of a compositecable to which the present invention is applied;

FIG. 2 is a cross-sectional view showing another example of thecomposite cable to which the present invention is applied;

FIG. 3 is a cross-sectional view showing still another example of thecomposite cable to which the present invention is applied; and

FIG. 4 is a cross-sectional view showing still another example of thecomposite cable to which the present invention is applied.

DESCRIPTIONS OF THE PREFERRED EMBODIMENTS

Next, one embodiment example of the present invention will be described.A composite cable according to the present embodiment is a compositecable configuring a composite harness used in a vehicle such as a car.More specifically, the composite cable according to the presentembodiment is a composite cable obtained by unifying an electric wire(EMB power supply wire) that supplies power to an electro-mechanicalbrake (EMB) with an electric wire (CAN signal wire) that transmits asignal for controlling the electro-mechanical brake by using a sharedsheath. In other words, the composite cable according to the presentembodiment is a multi-core cable including a plurality of power supplywires and signal wires. Hereinafter, a structure of the composite cableaccording to the present embodiment will be described in detail.

As shown in FIG. 1, a composite cable 1 according to the presentembodiment includes an assembly 2 made of a plurality of electric wiresand a sheath 3 formed around the assembly 2, and has an outer diameterof 8 mm to 12 mm. The assembly 2 includes two first electric wires 20and one shield electric wire 30. These three electric wires (two firstelectric wires 20 and one shield electric wire 30) are intertwined in afirst direction. In the present embodiment, the two first electric wires20 and the one shield electric wire 30 are intertwined in a clockwisedirection (intertwined in a right-hand turning direction) in a crosssection shown in FIG. 1. In other words, the two first electric wires 20and the one shield electric wire 30 are intertwined in an S twistmanner. In the following description, the assembly 2 is referred to as“electric wire assembly 2” in some cases. The sheath 3 of the presentembodiment is made of polyurethane.

The two first electric wires 20 included in the electric wire assembly 2are power supply wires that supply power to the electro-mechanicalbrake. Each of the first electric wires 20 includes: a core wire 21obtained by intertwining a plurality of copper wires or copper alloywires; and an insulator 22 covering the core wire 21. A diameter of eachof the plurality of copper wires or copper alloy wires configuring thecore wire 21 is 0.08 mm to 0.12 mm, and the insulator 22 is made of across-linked polyethylene. In the present embodiment, the two firstelectric wires 20 are in contact with each other.

The shield electric wire 30 included in the electric wire assembly 2includes: a stranded electric wire 32 obtained by intertwining aplurality of second electric wires 31 each having a smaller outerdiameter than that of the first electric wire 20; and a shield layer 33formed around this stranded electric wire 32. The stranded electric wire32 according to the present embodiment is made of two second electricwires 31 that are intertwined in a second direction that is opposite tothe first direction. That is, the two second electric wires 31configuring the stranded electric wire 32 are intertwined in acounterclockwise direction (intertwined in a left-hand turningdirection) in the cross section shown in FIG. 1. In other words, the twosecond electric wires 31 are intertwined in a Z twist manner.

As described above, in the present embodiment, an intertwining directionof the first electric wires 20 and the shield electric wire 30 (theelectric wire assembly 2) and an intertwining direction of the pluralityof second electric wires 31 configuring the stranded electric wire 32included in the shield electric wire 30 are the opposite direction toeach other.

The second electric wires 31 configuring the stranded electric wire 32are the CAN signal wires that transmit signals for controlling theelectro-mechanical brake. In the following description, the strandedelectric wire 32 is referred to as “twist pair wire 32” in some cases.That is, the shield electric wire 30 according to the present embodimentincludes: the twist pair wire 32; and a shield layer 33 formed aroundthis twist pair wire 32. Note that each of the second electric wires 31has the same basic structure as that of the first electric wire 20. Thatis, each of the second electric wires 31 includes a core wire obtainedby intertwining a plurality of copper wires or copper alloy wires; andan insulator covering the core wire. A diameter of each of the pluralityof copper wires or copper alloy wires configuring the core wire is 0.08mm to 0.12 mm, and the insulator is made of cross-linked polyethylene.In the present embodiment, the two second electric wires 31 are incontact with each other inside the shield layer 33. The shield electricwire 30 in the present embodiment is in contact with each of the twofirst electric wires 20 while apart itself in a circumferentialdirection is positioned at a gap between the two first electric wires20. Note that a wrapping part made of a non-woven fabric tape or a papertape may be arranged on an outer circumference of the shield electricwire 30. In this manner, the first electric wires 20 and the shieldlayer 33 are in contact with each other, so that an effect of preventingdamage of the insulator 22 can be obtained.

The shield electric wire 30 includes a first line filler 41 in additionto the twist pair wire 32 and the shield layer 33. More specifically, aportion between the twist pair wire 32 and the shield layer 33 is filledwith a plurality of first line fillers 41. In the present embodiment,the twist pair wire 32 and some of the plurality of first line fillers41 are in contact with an inner circumference of the shield layer 33. Onthe other hand, a portion between the electric wire assembly 2 and thesheath 3 is filled with a plurality of second line fillers 42. That is,the composite cable 1 includes: the plurality of first line fillers 41filled between the twist pair wire 32 and the shield layer 33; and theplurality of second line fillers 42 filled between the electric wireassembly 2 and the sheath 3. Note that a wrapping part made of anon-woven fabric tape or a paper tape maybe arranged between the twistpair wire 32/the first line fillers 41 and the shield layer 33. Thismanner causes such effects as causing the shield layer 33 to be easilyformed on an outer circumference of the twist pair wire 32 and the firstline fillers 41 and as preventing the damage of the insulators of thesecond electric wires 31 because of the contact between the secondelectric wires 31 and the shield layer 33.

Each of the first line fillers 41 included in the shield electric wire30 is a cord or yarn made of polyethylene, PET (polyethyleneterephthalate) or PP (polypropylene), and is intertwined together withthe two second electric wires 31 in the second direction. Each of thesecond line fillers 42 is a string made of polyethylene, PET(polyethylene terephthalate) or PP (polypropylene), and is intertwinedtogether with the first electric wires 20 and the shield electric wire30 in the first direction. The first line filler 41 and the second linefiller 42 are the same line filler as each other. However, a fillingrate of the first line fillers 41 is higher than a filling rate of thesecond line fillers 42. In other words, the first line fillers 41 aremore “dense” than the second line fillers 42, and the second linefillers 42 are more “sparse” than the first line fillers 41. In thepresent embodiment, note that the second line filler 42 is not arrangedin a gap between the two first electric wires 20 and the shield electricwire 30.

The “same” between the first line filler 41 and the second line filler42 described here means not only that the material (polyethylene) is thesame but also that a cross-sectional area is the same. That is, the linefillers that are the same as each other in the cross-sectional area arefilled between the twist pair wire 32 and the shield layer 33 andbetween the electric wire assembly 2 and the sheath 3, respectively. Thefilling rate of the line fillers (the first line fillers 41) between thetwist pair wire 32 and the shield layer 33 is higher than the fillingrate of the line fillers (the second line fillers 42) between theelectric wire assembly 2 and the sheath 3. Since the first line filler41 and the second line filler 42 have the same cross-sectional area aseach other, difference in the filling rate therebetween corresponds todifference in the number of the line fillers per unit cross-sectionalarea between the first line fillers 41 and the second line fillers 42.That is, the difference in the filling rate therebetween indicates thatthe number of the first line fillers 41 per unit cross-sectional area islarger than the number of the second line fillers 42 per unitcross-sectional area. Note that the individual cross-sectional areas ofthe first line fillers 41 and the second line fillers 42 vary onmanufacturing. The above explanation describing that the cross-sectionalareas of the first line filler 41 and the second line filler 42 are thesame as each other does not mean that such variation on themanufacturing is also eliminated.

As described above, the composite cable 1 according to the presentembodiment includes the plurality of first line fillers 41 filledbetween the twist pair wire 32 and the shield layer 33 and the pluralityof second line fillers 42 filled between the electric wire assembly 2and the sheath 3. In this manner, the shield electric wire 30 issuppressed from being compressed by a pressure, and deformation of itscross-sectional shape is suppressed, the pressure being caused by thefillers (the second line fillers 42) filled between the electric wireassembly 2 and the sheath 3 including the shield electric wire 30 inorder to maintain the cross-sectional shape of the entire compositecable 1. The filling rate of the first line fillers 41 is higher thanthe filling rate of the second line fillers 42. In other words, in thecomposite cable 1 according to the present embodiment, a filling densityof the line fillers is different between inside and outside of theshield electric wire 30 so that the filling density of the line fillersinside the shield electric wire 30 is higher than the filling density ofthe line fillers around the shield electric wire 30. In this manner, thedeformation of the cross-sectional shape of the shield electric wire 30is further suppressed. That is, while the cross-sectional shape of thecomposite cable 1 is maintained, the deformation of the cross-sectionalshape of the shield layer 33 formed around the signal wire 31 issuppressed. In this manner, even if the composite cable 1 is repeatedlybent, the possibility of the breakage of the shield layer 33 is low.

Further, in the composite cable 1 according to the present embodiment,the intertwining direction of the first electric wires 20, the shieldelectric wire 30 and the second line fillers 42 is opposite to theintertwining direction of the second electric wires 31 and the firstline fillers 41 configuring the stranded electric wire 32. In otherwords, the intertwining direction of the wire materials outside theshield layer 33 is opposite to the intertwining direction of the wirematerials inside the shield layer 33. Therefore, deforming tendency ofthe intertwining of the first electric wires 20, the shield electricwire 30 and the second line fillers 42 and deforming tendency of theintertwining of the second electric wires 31 and the first line fillers41 are canceled by each other, and linearity of the entire compositecable 1 is improved. As a result, the composite cable 1 is easily routedin a predetermined region. The contact between the routed compositecable 1 and peripheral components is also prevented.

The present invention is not limited to the foregoing embodiments, andvarious alterations can be made within the scope not changing theconcept. For example, the shield layer 33 according to the presentembodiment is a braided shield obtained by braiding a plurality of metalwires each made of copper or others. However, the shield layer 33 is notlimited to the braided shield. The shield layer 33 maybe, for example, aserved (laterally-wound) shield that is helically wound on an outercircumference of the twist pair wire 32. In the above-describedembodiment, the shield layer corresponding to the shield layer 33 is notformed around the first electric wires 20. As a result, the firstelectric wires 20 and the second line fillers 42 are directly in contactwith each other. However, an embodiment of arrangement of the shieldlayer corresponding to the shield layer 33 around the first electricwires 20 is also applicable.

As shown in FIG. 2, an embodiment of arrangement of an earth wire 50 isalso applicable. The illustrated earth wire 50 is intertwined in thefirst direction (intertwined clockwise) together with the first electricwires 20, the shield electric wire 30 and the second line fillers 42.

As shown in FIG. 3, an embodiment of arrangement of a braided shield 51inside the sheath 3 is also applicable. Note that FIG. 3 schematicallyshows the cross-sectional structure of the composite cable 1.

As shown in FIG. 4, an embodiment of usage of first line fillers 41 andsecond line fillers 42 each having a larger diameter than those of theline fillers shown in FIGS. 1 and 2 is also applicable. In theembodiment shown in the drawing, two second line fillers 42 are formedoutside the shield layer 33, and two first line fillers 41 are formedinside the shield layer 33.

The cross-sectional areas of the first line filler 41 and the secondline filler 42 shown in FIG. 4 are different from each other. However, aratio of the cross-sectional areas of the first line fillers 41 to thecross-sectional area of the shield electric wire 30 is larger than aratio of the cross-sectional areas of the second line fillers 42 to thecross-sectional area of the composite cable 1. In other words, when itis assumed that a cross-sectional area of a region inside the shieldlayer 33 in the entire cross-sectional area of the composite cable 1 isan “inner cross-sectional area” while a cross-sectional area of a regionoutside the shield layer 33 therein is an “outer cross-sectional area”,a ratio of the cross-sectional areas of the first line fillers 41 to theinner cross-sectional area is larger than a ratio of the cross-sectionalareas of the second line fillers 42 to the outer cross-sectional area.That is, the filling rate of the first line fillers 41 is higher thanthe filling rate of the second line fillers 42. Therefore, also in theembodiment shown in FIG. 4, the shield electric wire 30 is suppressedfrom being compressed by a pressure caused by the second line fillers42, and its cross-sectional shape does not deform.

An embodiment of the usage of the first line fillers 41 and the secondline fillers 42 each being such as a cord, a yarn or a thread made of amaterial other than polyethylene is also applicable. For example, anembodiment of the usage of the first line fillers 41 and the second linefillers 42 each being a spun rayon yarn is also applicable.

An embodiment of the usage of the sheath 3 made of a material (such asethylene propylene diene rubber (EPDM)) other than polyurethane is alsoapplicable. An embodiment of the usage of the insulator 22 made of amaterial (such as fluorocarbon resin) other than the cross-linkedpolyethylene is also applicable.

An embodiment of the winding of the wrapping tape such as the non-wovenfabric tape or the paper tape around the first line fillers 41 and thesecond line fillers 42 is also applicable. In this case, the wrappingtape may be laterally wound or longitudinally wound.

The intertwining direction of the first electric wires 20 and the shieldelectric wire 30 and the intertwining direction of the second electricwires 31 configuring the stranded electric wire 32 are not limited tothe directions shown in FIG. 1 and others as long as these directionsare opposite to each other. That is, an embodiment of the intertwiningof the first electric wires 20 and the shield electric wire 30 in acounterclockwise direction in the cross section shown in FIG. 1 andothers and the intertwining of the plurality of second electric wires 31configuring the stranded electric wire 32 in a clockwise direction inthe cross section shown in FIG. 1 and others is also applicable.

The numerical values and the ranges of the numerical values described inthe present specification are only one example. The numbers of and thetypes of the electric wires included in the composite cable of thepresent invention can be appropriately added, eliminated and changed inaccordance with the application of the composite cable. The presentinvention is also applicable to a composite cable other than thecomposite cable used for the vehicle wire harness. On the other hand,the composite cable to which the present invention is applied has suchan advantage effect as causing the inner electric wires to be difficultto be compressed at the time of the bending. In this viewpoint, thepresent invention is suitable to be applied to a composite cable usedwhen the bending is repeated. For example, the present invention isparticularly suitable to be applied to a composite cable or others thatis routed along an arm of an industrial robot and that is repeatedlybent in accordance with movement of the arm.

What is claimed is:
 1. A composite cable comprising: a plurality offirst electric wires; a shield electric wire in which a shield layer isformed around a stranded electric wire obtained by intertwining aplurality of second electric wires; a sheath formed around an assemblyobtained by intertwining the plurality of first electric wires and theshield electric wire; a first line filler filled between the strandedelectric wire and the shield layer; and a second line filler filledbetween the assembly and the sheath, wherein the plurality of firstelectric wires and the shield electric wire are intertwined in a firstdirection while the plurality of second electric wires included in theshield electric wire are intertwined in a second direction that isopposite to the first direction.
 2. The composite cable according toclaim 1, wherein the second line filler is intertwined in the firstdirection together with the first electric wires and the shield electricwire, and the first line filler is intertwined in the second directiontogether with the second electric wires.
 3. The composite cableaccording to claim 1, wherein a filling rate of the first line filler ishigher than a filling rate of the second line filler.
 4. The compositecable according to claim 3, wherein the first line filler and the secondline filler have the same cross-sectional area as each other, and thenumber of the first line filler per unit cross-sectional area is largerthan the number of the second line filler per unit cross-sectional area.5. The composite cable according to claim 1, wherein the first electricwire and the second line filler are directly in contact with each other.